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Physics - Concepts - Velocity and Acceleration

An object in motion is said to have velocity or acceleration. While we are all used to the word "speed," this word does not truly quantify any useful measurements in science since it is a measure of scale.

Velocity is the preferred measure of "speed" when dealing with anything scientific as it can be quantified based on distance traveled. This is presented by some number over distance traveled - like 70 km/h.

This formula demonstrates how velocity is determined:


Acceleration is another one of those tricky words. We are familiar with the accelerator pedal (gas pedal) on a car, and rightly defined as detonating additional gas and air produces more combustion resulting in a faster turning engine. However, this is only half of the story.

Acceleration is defined as any change in vector. This means that a car that speeds up, slows down, turns left and turns right is undergoing acceleration. We have already seen velocity: distance traveled in a particular time frame. This is taking into account a constant speed. In order to determine acceleration, we need to document any changes in velocity over time:


To add to some confusion, it is possible to have negative acceleration. An example would be a car traveling in reverse. A car slowing down is also negative acceleration due to opposing forces.

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